[b]Tips on detecting an autopen[/b]
An autopen's signature is slightly shaky as the autopen vibrates.
Autopens come to abrupt halt at the end and may leave a noticeable spot of ink.
Autopens do not always create an identical signature due to the machine moving accidentally or by using multiple templates with different signatures. Some notables who use several different templates therefore creating different autopen signatures are Bill Clinton, Margaret Thatcher and Tony Blair.Therefore comparing signatures to other known autopens don't always work. If comparing a signature and any part of that signature is exact it's most likely an autopen.
A light signature, especially one that does not have variation in pressure as seen by an indentation in the paper when viewed in the proper light . UV light is the best way to see this as well as determining preprints.
However be careful of an autograph that's indentation is very notcable as it may be signed by a laser printer.
A “drawn” look to the signature.
Also autopens sign in straight choppy lines that are naked to the human eye. AE: -----
However autopens are getting better .
[b]Stamped signatures [/b]are very easy to identify as the Stamped signatures have a “drawn” look, and will have inconsistent ink distribution. Blotchy.
[b]Secretarials [/b]are a never ending arguement on here These are sometimes the most difficult to spot, since the secretary is sometimes very good at duplication of the celebrity’s handwriting. Again, references and periodicals will help you determine what is real and what is fake. To help determine if a signature is real or a forgery, obtain a known sample of the signature from in-person examples in these sources. Compare the two carefully. A good tip to remember is to turn the signatures upside-down when examining them—this will eliminate certain biases formed when one’s mind perceives the letters of the name instead of its form. Secretarial signatures are often more carefully drawn and are more compact than the authentic signature. Also common sense goes along way if a celeb lives in Idaho and your sending mail to calif. and receive it back in 8 days from calif. the odds of that celeb signing your pic. is slim to none. Another great example you send your pics to a celeb in Los Angeles, The celeb lives in san francisco or is out of the country and you receive your pics. signed from Texas. That's definately a red flag.
Many inexperienced collectors make the mistake that an autograph must be real if a letter comes with it that says the celebrity signed the item being sent. Sometimes this is simply a trick some secretaries use to make their forgeries seem real. For example, secretarial signatures sent from Lyndon Johnson’s office often came with an accompanying letter that said “The President was very happy to sign the enclosed photo. It comes with his best wishes.”

Experience is the only key to authenticating autographs. Until you gain enough experience to authenticate signatures (which takes years of careful research) you must assume that all autographs in your collection are capable of being fakes. Such is the harsh reality of autograph collecting.
Expect about 30-60% of responses through the mail to be fakes, depending upon which celebrities you choose to collect. Entertainment figures are notorious about sending fakes, as with sports figures.
Hope this helps.

An autopen is usually identified by comparing the signature to other signatures by the same celebrity. Autopenned autographs will be exactly the same although the placement on the photo may be different. Autopens are sometimes "shaky" due to movement of the machine when in use. However, the most notable trait that defines an autopen is the uniform appearance of the signature. The entire signature will be of the same thickness.
Stamped autographs are fairly easy to recognize. Once again the signatues will be the exact same, so it is usually easy to distinguish stamps by comparing the signature with another one.

How do you recognize a Autopen or Stamp?